```Python
with open("file.txt") as file:
    file.read()
```

Em versões mais recentes do Python, há também um **gerenciador de contexto assíncrono**. Você o usaria com `async with`:

```Python
async with lifespan(app):
    await do_stuff()
```

/**
 * A {@link Graph} whose elements and structural relationships will never change. Instances of this
 * class may be obtained with {@link #copyOf(Graph)}.
 *
 * <p>See the Guava User's Guide's <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#immutable-implementations">discussion
 * of the {@code Immutable*} types</a> for more information on the properties and guarantees
 * provided by this class.

/**
 * A {@link ValueGraph} whose elements and structural relationships will never change. Instances of
 * this class may be obtained with {@link #copyOf(ValueGraph)}.
 *
 * <p>See the Guava User's Guide's <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#immutable-implementations">discussion
 * of the {@code Immutable*} types</a> for more information on the properties and guarantees
 * provided by this class.

	if err := tx.First(&User{}, "name = ?", user.Name).Error; err != nil {
		t.Fatalf("Should find saved record")
	}

	if err := tx.SavePoint("save_point1").Error; err != nil {
		t.Fatalf("Failed to save point, got error %v", err)
	}

	user1 := *GetUser("transaction-save-point-1", Config{})
	tx.Create(&user1)

	if err := tx.First(&User{}, "name = ?", user1.Name).Error; err != nil {

/**
 * A {@link ValueGraph} whose elements and structural relationships will never change. Instances of
 * this class may be obtained with {@link #copyOf(ValueGraph)}.
 *
 * <p>See the Guava User's Guide's <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#immutable-implementations">discussion
 * of the {@code Immutable*} types</a> for more information on the properties and guarantees
 * provided by this class.

    and match them against the toolchain requirements of the project (as configured in {@code pom.xml}):
    if match is found, the toolchain instance is made available to other Maven plugins.</p>
    <p>With {@code jdk} toolchain, for example, instead of being stuck with the JDK used to run Maven, all plugins can use

            "There are currently no logon servers available to service the logon request.", "The specified user already exists.",
            "The specified user does not exist.", "The specified network password is not correct.",
            "Logon failure: unknown user name or bad password.", "Logon failure: user account restriction.",

            "There are currently no logon servers available to service the logon request.", "The specified user already exists.",
            "The specified user does not exist.", "The specified network password is not correct.",
            "Logon failure: unknown user name or bad password.", "Logon failure: user account restriction.",

        // Make attempts from same IP with different users
        for (int i = 1; i <= 5; i++) {
            assertTrue(rateLimiter.checkAttempt("user" + i, ip), "Attempt " + i + " should be allowed");
            rateLimiter.recordFailure("user" + i, ip);
        }

        // 6th attempt from same IP should be blocked
        assertFalse(rateLimiter.checkAttempt("user6", ip), "Should block after IP rate limit");
    }

/// note | 技術詳細

レスポンスモデルは、関数の戻り値のアノテーションではなく、このパラメータで宣言されています。なぜなら、パス関数は実際にはそのレスポンスモデルを返すのではなく、`dict`やデータベースオブジェクト、あるいは他のモデルを返し、`response_model`を使用してフィールドの制限やシリアライズを行うからです。

///

## 同じ入力データの返却

ここでは`UserIn`モデルを宣言しています。それには平文のパスワードが含まれています:

{* ../../docs_src/response_model/tutorial002.py hl[9,11] *}

そして、このモデルを使用して入力を宣言し、同じモデルを使って出力を宣言しています:

{* ../../docs_src/response_model/tutorial002.py hl[17,18] *}